The Abyss Worm is an enemy from Crisis Core -Final Fantasy VII-.
Abyss Worm is vulnerable to both physical and magical attacks, but its high Attack and Magic ratings make it a tough foe to defeat. Cast Gravity to deplete half of its HP, continued with a barrage of Blizzaga. Try to use Hell Blizzaga if you have it. This will cause some status effects, and a large amount of damage. Costly Punch works well, too. Have protection against Stop as it can easily inflict it with Absolute Stop Thread, leaving the player wide open to other attacks and easily defeated.
Abyss refers to a bottomless pit, to the underworld, to the deepest ocean floor, or to hell, or more loosely to any chasm or large drop.